The invention relates to a procedure for the isolation and enrichment of nucleated fetal erythrocytes (hereinafter NFEs) from maternal blood during the early stages of pregnancy, particularly for subsequent prenatal diagnosis such as by in situ hybridization.
Several devices and methods have been developed for separation of blood components, particularly for separation of red blood cells, platelets, leukocytes and plasma from one another. See, for example, U.S. Pat. Nos. 4,880,548, 4,923,620 and 4,925,572 incorporated herein by reference. These methods and devices have been directed at separation of whole blood components for blood banking of packed erythrocytes or packed platelets from which fibrinogen and/or fibrin gels, microaggregates, and leukocytes have been removed, transfusion or therapeutic, particularly emergency, administration of individual concentrated components usually in relatively large volumes, i.e., one or more units (450 ml. each).
The number of NFEs present in maternal blood is very low (estimates are from 1 in 10,000 to 1 in 1,000,000). The current state of the art does not permit the isolation of these cells mainly because of the presence of large numbers of maternal cells.